The magnetic properties of the ferrimagnetic cobaltite CaBaCo_ 4O_7 are systematically investigated. We find that the susceptibility exhibits a downward deviation below ～360 K, suggesting the occurrence of short-range magnetic correlations at a temperature well above ~(TC). The effective moment is determined to be 4.5μBf.u., which is consistent with that expected for the Co~(2+)Co~(3+) high spin species. Using a criterion given by Banerjee Phys. Lett. 12 (1964) 16, we demonstrate that the paramagnetic to ferrimagnetic transition in CaBaCo_4O_7 has a first order character.
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